Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, non-destructive, and open-world behavior. The description adds material behavioral context beyond annotations: pricing via x402 or credits, API key usage, free first 5 paid calls per day, country coverage, and verdict outcomes.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loads the use case, then compresses country coverage into a compact semicolon list, followed by verdict and payment details. It is dense but every clause carries coverage, cost, or auth information; minor density keeps it from a 5.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a complex paid, multi-country, read-only tool with no output schema, the description supplies country coverage, verdict categories, payment/auth details, and API key placement. It does not clarify the minimum identifier needed when all five parameters are optional, though the schema covers parameter documentation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so all five parameters are already documented in the schema, including id, kvk, name, api_key, and country. The description restates country support and Dutch KvK insolvency meaning but adds little parameter-level meaning beyond the schema, so baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource: check whether a European company is healthy, with enumerated country-specific signals and a clear verdict scale. The health-check focus is distinguishable from generic lookup/dossier siblings, but the description never names or contrasts those alternatives, so it falls short of full sibling differentiation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives a clear usage context: use before dealing with a European company, and specifies which countries and signals are covered. It does not state when not to use it or explicitly route agents to company_lookup, company_dossier, or eu_company_check, so it lacks exclusions/alternatives.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.